Some moral codes are sets of laws without a clear focus. Other moral codes have a focus like following the right path or becoming a noble person -- but the direction of the right path may not be well-defined; what makes someone a noble person may again lead to an unfocused list of principles and goals to attain.
With Jesus, the right path is defined in terms of love. Of all the commands his people already had in their moral code, he singled out these as the greatest: Love God with all your heart, soul, mind, and strength; and love your neighbor as yourself. He also summed up: "Do unto others as you would have them do unto you," adding, "This is the law and the prophets" (the whole of the divine commands). As an early Jewish convert said, "Love does no harm to its neighbor, therefore love is the fulfillment of the law."
Basing morality on love makes a big difference in how morality is lived. Love cannot be cold or joyless. It forbids us from dehumanizing each other, even in the name of "the greater good" -- especially in the name of the greater good, if that greater good is love. It prevents viewing and treating people as enemies. It leads us towards companionship and fellowship. It causes us to know each other and build ties in common with each other. It is fulfilled in friendship and family, in hospitality and in knowing our neighbors. It is a living, growing source of goodwill.